Gloss fibers coated with a size comprising a film-farming binder and an amino acid

ABSTRACT

A composition for use in the treatment of glass fibers, and preferably in the treatment of glass fibers to form a size coating thereon to facilitate contact of the glass fibers with resinous and elastomeric materials in the manufacture of glass fiber reinforced resins and glass fiber reinforced elastomeric products wherein the size composition is formulated to contain, as the essential ingredients, a film-forming binder and an amino acid as a coupling agent. Bundles of glass fibers sized with the composition of this invention are particularly well suited for impregnation with an elastomer compatible material containing a resorcinol-aldehyde resin component and an elastomer component for use in the manufacture of glass fiber reinforced elastomeric products. Polyamines may also be used as coupling agents instead of the amino acids.

United States Patent 1191 Flautt et al.

[75] Inventors: Martin C. Flautt, Granville; Kevin M. Foley, Hebron;Richard M. I-Iaines, Warsaw, all of Ohio [73] Assignee: Owens-CorningFiberglas Corporation, Toledo, Ohio [221 Filed: Aug. 6, 1973 21 Appl.No.: 386,143

[52] US. Cl...... 260/4 R; 260/29.2 E; 260/29.2 EP; 260/29.6 N; 260/29.6MN; 260/29.7 N;

[51] Int. Cl B32b 17/04; B32b 17/10 [58] Field of Search 117/54, 124 D,126 GB, 117/126 60, 72; 260/29.6 N, 29.6 MN, 29.7

N, 29.2 E, 29.2 EP

[56] References Cited UNITED STATES PATENTS 2,184,320 12/1939 Simpson117/126 GQ 2,688,007 8/1954 Sternman 117/126 GB 2,796,362 6/1957 Wooding117/72 2,943,011 6/1960 Rayner 117/72 3,224,998 12/1965 Kirkconnell260/42. 16

3,296,174 1/1967 Pickard 428/441 3,325,105 6/1967 Veltman 241/163,676,287 7/1972 Flautt 1l7/126 GB 3.719.520 3/1973 Fujimoto 117/126 GB3,769,064 10/1973 Greenlee... 3,802,909 4/1974 Rochett 117/100 B OTHERPUBLICATIONS Chemical Abstracts, Vol. 53:5706a. Chemical Abstracts, Vol.72:33324y.

Primary Examiner-William D. Martin Assistant ExaminerWilliam H. SchmidtAttorney, Agent, or FirmCarl G. Staelin; John W. Overman; Keith V.Rockey [57] ABSTRACT A composition for use in the treatment of glassfibers, and preferably in the treatment of glass fibers to form a sizecoating thereon to facilitate contact of the glass fibers with resinousand elastomeric materials in the manufacture .of glass fiber reinforcedresins and glass fiber reinforced elastomeric products wherein the sizecomposition is formulated to contain, as the essential ingredients, .afilm-forming binder and an amino acid as a coupling agent. Bundles ofglass fibers sized with the composition of this invention areparticularly well suited for impregnation with an elastomer compatiblematerial containing a resorcinol-aldehyde resin component and anelastomer component for use in the manufacture of glass fiber reinforcedelastomeric products. Polyamines may also be used as coupling agentsinstead of the amino acids.

11 Claims, 3 Drawing Figures US. Patent Oct. 21, 1975 3,914,192

GLOSS FIBERS COATED WITH A SIZE COMPRISING A FILM-FARMING BINDER AND ANAMINO ACID This invention relates to a size composition, and moreparticularly to a size composition for use in the treatment of glassfibers to improve the processing and performance characteristics ofglass fibers in the manufacture of glass fiber reinforced elastomericproducts and glass fiber reinforced plastics.

As used herein, the term glass fibers" is intended to refer to andinclude (1) continuous fibers formed by the rapid attenuation ofhundreds of streams of molten glass and to strands formed when suchcontinuous glass fiber filaments are gathered together in forming; andto yarns and cords formed by plying and/or twisting a number of strandstogether, and to woven and nonwoven fabrics which are formed of suchglass fiber strands, yarns or cords, and (2) discontinuous fibers formedby high pressure steam or air directed angularly downwardly ontomultiple streams of molten glass issuing from the bottom side of a glassmelting bushing and to yarns that are formed when such discontinuousfibers are allowed to rain down gravitationally onto a foraminoussurface wherein the fibers are gathered together to form a sliver whichis drafted into a yarn; and to woven and non-woven fabrics formed ofsuch yarns of discontinuous fibers, and (3) combinations of suchcontinuous and discontinuous fibers in strands, yarns, cords and fabricsformed thereof.

It is well known to combine glass fibers with resins and withelastomeric materials in the manufacture of glass fiber reinforcedplastics and in the manufacture of glass fiber reinforced elastomericproducts. One of the primary difficulties in the combination of glassfibers with resins and with elastomeric materials has resided in theinability to securely bond the glass fibers to the resin or elastomericmaterial. It is believed that the inability to establish a secure bondbetween glass fibers and resins or elastomeric materials stems at leastin part from the fact that glass fibers have a completely smooth,rod-like configuration to thereby render it difficult to establish anyphysical bond between the glass fibers and the resin or elastomericmaterial. It is believed that the inability to establish a securebonding relationship also stems from the fact that glass fibers havesurfaces which are highly hydrophilic and thus form a thin film ofmoisture on the individual glass fiber surfaces almost immediately afterthe glass fibers are formed. This film of moisture serves to destroy anybond, whether chemical or physical, which may other wise be establishedbetween the glass fiber surfaces and the resins or elastomericmaterials.

Substantial progress has been made in the treatment of glass fibers foruse as reinforcement for resins and for elastomeric materials. It is nowconventional practice to coat glass fibers, preferably as they areformed, with a size composition to impart to the individual glass fiberfilaments the desired degree of lubricity to prevent destruction of thefibers through mutual abrasion without destroying the fibrouscharacteristics of the glass fibers. The thin film or size coatingapplied to the individual glass fibers not only serves to protect thefibers from mutual abrasion as described above, but also tends to impartto the glass fibers somewhat hydrophobic surface characteristics tothereby prevent or at least substantially minimize the formation of athin moisture film on the glass fiber surfaces.

Size compositions now in commercial use in the manufacture of glassfiber reinforced resins and glass fiber reinforced elastomeric materialsembody a coupling agent, preferably in the form of an organo siliconcompound. Such organo silicon coupling agents most frequently take theform of an organo silane containing 1 to 3 readily hydrolyzable groupssuch as alkoxy or halogen groups, and at least one and up to threeorganic groups attached directly to the silicon atom in which theorganic groups are substituted by a functional group, such as an aminogroup, an epoxy group, a mercapto group or the like. It is generallybelieved that the hydrolyzable groups are subjected to hydrolysis in thesize composition to thereby permit the silicon atom of the silane to bechemically bonded to the'glass fiber surface while the organic groupextends outwardly from the glass fiber surface.

While the use of such silanes as described above has represented asubstantial improvement in the manufacture of glass fiber reinforcedresins and glass fiber reinforced elastomeric products, the silanes usedcommercially at the present time are quite expensive and thus can beused in only limited amounts without significantly contributing to thecosts of the reinforced materials.

It is accordingly an object of the present invention to provide acomposition for use in the treatment of glass fibers to improve theprocessing and performance characteristics of glass fibers for use inthe manufacture of glass fiber reinforced resins and glass fiberreinforced elastomeric products. 7

It is a related object of the invention to provide a composition for usein the treatment of glass fibers to improve the bonding relationshipwith elastomeric materials in the manufacture of glass fiber reinforcedelastomeric products.

It is another object of the invention to provide a composition for usein the treatment of glass fibers which is effective to promotecompatibility between treated glass fibers and thermoplastic andthermosetting resins in the manufacture of glass fiber reinforcedresinous products.

It is another and more specific object of the present invention toprovide a composition for use inthe treatment of glass fibers in whichthe composition is formulated to contain an inexpensive coupling agentwhich is capable of establishing a secure bonding relationship betweenthe treated glass fibers and elastomeric and resinous materials.

It is a further object of the invention to provide treated glass fiberswhich can be employed in the manufacture of glass fiber reinforcedelastomeric products and glass fiber reinforced resin products.

These and other objects and advantages of the invention will appear morefully hereinafter and for the purpose of illustration, and not oflimitation, embodiments of the invention are shown in the accompanyingdrawings in which:

FIG. 1 is a cross-sectional view of glass fibers which have been sizedwith the composition of this invention;

FIG. 2 is a cross-sectional view of a bundle of glass fibers in whichthe individual glass fibers have been sized with the composition of thisinvention and formed into a bundle which is impregnated with anelastomer compatible material; and

FIG. 3 is a cross-sectional view of glass fibers employed asreinforcement for a resinous material.

The concepts of the present invention reside in a composition for use inthe treatment of glass fibers to form a thin film or size coating on theindividual glass fiber filaments in which the composition is formulatedto contain a film-forming binder and, as a coupling agent, an aminoacid. It has surprisingly been found that amino acids are effective ascoupling agents to es tablish a secure bonding relationship between thetreated glass fibers and resinous materials and elastomeric materialswith which the treated glass fibers are combined in the manufacture ofglass fiber reinforced resinous products and glass fiber reinforcedelastomeric products. Without limiting the present invention as totheory, it is believed that the effectiveness of the amino acids ascoupling agents is due at least in part to the ability of amino acids toform polyamides in situ on the glass fiber surfaces by alignment of theamino acids in a head-to-toe relationship whereby the carboxy group ofthe molecule of the amino acid reacts with a primary or secondary aminogroup of an adjacent molecule to form an amide linkage.

In the practice of the present invention, a number of amino acids can beemployed as coupling agents. Preferably, use is made of amino acidscontaining terminal amino groups such as those having the generalformula wherein x is an integer from I to l 1. Representative ofsuitable amino acids include glycine, beta-alanine, 3- amino-butyricacid, 4 aminopentanoic acid, etc. Also contemplated for use in thepractice of this invention are the natural amino acids containing morethan one amino group, such as asparagine, lysine, etc.

As indicated above, the size compositionof this invention is formulatedto include, in addition to the amino acid coupling agent describedabove, a film forming binder in the form of an aqueous dispersion. Anumber of such binders can be employed in the practice of this inventionand include water soluble and water insoluble resinous materials. In thepreferred practice of this invention, the film forming binder is apolyolefin, such as polyethylene, polypropylene, copolymers of ethyleneand propylene, as well as numerous others. One film forming binder whichhas been found particularly well suited for use in the composition ofthis invention is a polyethylene marketed by Commercial SolventsCorporation under the trademark Quaker Quasoft HS-60". However, otherfilm forming binders can be employed, including polymers of butadiene;resinous copolymers of maleic anhydride and unsaturated monomers such asa conjugated diene, alkyl acrylate or methacrylate or a vinyl aromaticmonomer; polyvinyl alcohol; polyvinyl acetate; polyvinyl chloride;polyepoxides; polyesters; and other wellknown film forming materials.

The amount of the film forming binder and the amino acid coupling agenteach in the composition of this invention can be varied within widelimits. For best results, it is preferred to employ a composition whichcontains the binder in an amount within the range of 2 to by weightbased upon the weight of the composition, and the amino acid couplingagent in an amount within'the range of 0.5 to 57? by weight of thedispersion. However, since the amino acids employed in the practice ofthis invention as coupling agents are significantly less expensive thanthe organo silicon coupling agents employed by the prior art. greateramounts of the amino acids can be used if desired.

As is known to those skilled in the art, the amino acids are generallywater soluble and thus can simply be dissolved in an aqueous dispersioncontaining thefilm forming binder. However, is has been found that thestability of the size composition of this invention can be significantlyimproved by formulating the composition to include an organicsolubilizing agent which serves to prevent coagulation of the dispersionof the film forming binder by the amino acid. For this purpose it hasbeen found that secondary and tertiary lower alkanols containing 3 to 6carbon atoms can be employed. Representative alkanols includeisopropanol, isobutanol, tert-butanol, etc. Since the solubilizingagents are either secondary or tertiary alcohols, they are sufficientlyinert, with respect to the amino acids, to prevent or substantiallyminimize ester formation. The amount of solubilizing agent employed isnot critical to the practice of this invention and should be an amountto secure a stable system. Best results are usually achieved when thecomposition contains from 0.1 to 6.0% by weight of the solubilizingagent.

The composition of this invention is preferably applied to glass fibersas they are formed, but can also be applied after forming, if desired,to form a thin film or coating on the individual glass fiber filaments.As described above, it is believed that the amino acids tend to react toform polyamides on the glass fiber surfaces as the treated glass fibersare subjected to an elevated temperature such as during drying and/orcuring or vulcanizing of the treated glass fibers in combination withelastomeric materials or resinous materials in the manufacture of glassfiber reinforced elastomeric products and glass fiber reinforcedresinous products. Thus, the combination of the film forming binder andthe amino acid is believed to form a tough film on the glass fibersurfaces which is capable of securely integrating the treated glassfibers with elastomeric and resinous materialsf In the preferredpractice of the present invention, the glass fibers are coated informing with the size composition 'of this invention and the resultingcoated fibers are dried at an elevated temperature and preferably atemperature within the range of to 300C. The resulting coated fibers areillustrated in FIG. 1 wherein the size composition of this inventionforms a thin film or coating 10 on the individual glass fiber filaments12. As

described above, the thin film or size coating 10 on the sultingstrands. The resulting bundles can be directly 1 combined withelastomerie materials in the manufacture of glass fiber reinforcedelastomeric products without further treatment whereby the thin sizecoating serves to tie the glass fibers to the elastomeric material.However, in accordance with the preferred practice of this invention,the glass fibers which have been sized with the composition of thisinvention, are preferably formed into bundles and the bundlessubjectedto impregnation with an elastomer compatible material,preferably in the form of a blend of a resorcinolaldehyde resincomponent and at least one elastomer component. Such impregnatingcompositions are well known to those skilled in the art and aredescribed in US. Pat. Nos. 3,391,052; 3,402,064; 3,424,608; 3,506,476;3,533,830; 3,567,671; 3,591,357 and numerous others. While the relativeproportions of the resorcinol-aldehyde resin and the elastomer componentare not critical, it is generally preferred to employ an impregnantcontaining from 2 to parts by weight of the resorcinol-aldehyde resinfor each to 60 parts by weight of the elastomer component.

lmpregnation of the bundles of glass fibers which have been previouslysized with the composition of this invention can be carried out in anydesired manner. It is generally preferred to employ the immersionimpregnation technique as described in U.S. Pat. No. 3,424,608, in whichthe bundle of sized glass fibers is immersed in an aqueous bath of theimpregnating composition and subjected to a sharp bend while immersed inthe bath to open the bundle and thereby facilitate complete penetrationof the bundle by the solids of the impregnating composition. In theresulting bundle, which is illustrated in FIG..2 of the drawing, theimpregnant 14 serves to completely penetrate the bundle to fill theinterstices between the individually sized glass fiber filaments and toseparate the sized filaments each from the other. It has been found thatimpregnated bundles treated in this manner are particularly well suitedfor use as glass fiber reinforcements in elastomeric products, such asrubber tires, drive belts, timing belts and like products.

However, it will be understood by those skilled in the art that glassfibers which have been sized with the composition of this invention canalso be employed as reinforcement of resinous materials, such aspolyepoxides, polyesters, polyamides, melamine-urea or phenolic aldehyderesins and like thermoplastic and thermosetting resins. It is believedthat the tough film which is formed on the individual glass fibersurfaces by the application of the size coating of this invention servesto securely bond the glass fiber surfaces to such resinous materials.

A. glass fiber reinforced resinous product is illustrated in P16. 3 ofthe drawing. As can be seen from this figure, a resinous material 16forms a continuous phase in which the individually coated or sized glassfiber filaments 12 having the size coating 10 on the surfaces thereofare dispersed.

While not equivalent to the amino acid coupling agents described above,it has also been found that polyamines containing poly(oxyalkylene)groups can also be employed in coupling agents to promote a securebonding relationship between glass fibers and resinous and elastomericmaterials in the manufacture of glass fiber reinforced resinous productsand glass fiber reinforced elastomeric products. The polyaminescontemplated for use in the present invention have the general formulawherein y is an integer to provide an average molecular weight of 200 to2000. The foregoing amines are commercially available from JeffersonChemical Co. and have average molecular weights ranging up to about2000.

It has surprisingly been found that the foregoing amines can besubstituted for the amino acid coupling agent of this invention toprovide a size composition which is similarly capable of establishing asecure bonding relationship between glass fibers and elastomeric orresinous materials.

The amines described above have been used for a number of years as glassfiber lubricants in glass fiber size compositions. However, suchcompositions have always embodied, in addition to a film formingmaterial or binder, an organo silicon compound anchoring agent and,thus, the prior art has not recognized that these amines are effectiveas coupling agents in their own right in the absence of an organosilicon type anchoring agent. i

Having described the basic concepts of the present invention, referenceis now made to the following examples whichare provided by way ofillustration, and not by way o'fl-imitation, of the practice of theinvention in formulating the composition of the invention and thetreatment of glass fibers in accordance with the invention.

EXAMPLE 1 This example demonstrates the effectiveness of amino acids ascoupling agents in treated glass fibers for use as reinforcement forelastomeric materials as compared to organo silicon compounds of thetype widely used by the prior art.

A series of seven size compositions was formulated, varying only in thecoupling agent employed. The components of each of the size compositionswere as follows:

Size Composition Polyethylene (Quaker Quasoft HS60) 12% by wt.Solubilizing agent (isopropanol) 1.5% by wt. Coupling agent 1.5% by wt.Water 85% by wt.

Impregnating Composition Parts by Weight Resorcindl-Fnrmaldehyde resin(Penacolite R2170) solids Butadiene-styrene vinyl pyridine impregnatingComposition-Continued Parts by Weight EXAMPLE 3 This example illustratesthe use of a polyamine as a coupling agent for glass fibers asreinforcement for resterpolymcr (Gcntac FS) 42% solids 900 Vinylchloridc vinylidcnc chloride materlals' copolymer (Dow Latex 874) 50%solids 350 Using the procedure described in Example 1, a seriesMicro-Crystalline P f WHX of size compositions are formulated withvarious cou- (Vultex Wax Emulsion No.5) h h f H 56% Solids 200 p mgagents in accordance wit t e o owing 10 Size Composition Each of theimpregnated bundles thus produced was Polyethylene (Quaker ouasofl $60)120,7! by M. then molded between two strips of rubber and the buniz ngagent i prupan l) 1.5% by wt.

Coupling agent 1.5% by wt. dies were then sub ected to adhesion tests todetermine water 850,7 by wt the amount of force required to pull theimpregnated bundle from between the strips of rubber. The results ofthese tests are shown in the following table: Glass fibers were thensized with each of the size TABLE I compositions and incorporated with apolyester in the manufacture of glass fiber reinforced polyester rods.

CO A t Adh d Each rod thus produced was tested for flex strength to InCH CSIOI'I oun S p g g p compare the adhesion of the sized glass fiberswith the Glycine 43 polyester resinous material. The results of thesetests i are shown in the following table: 3-aminobutyric acid 47Gamma-aminopropyltriethoxysilane 12 T bl [IN-(beta-aminoethyl)gamma-aminopropyltriethoxysilane 20Garnma-glycidoxypropyltrimethoxysilane 28 Flex strengthGamma-mcrcaptopropyltrimethoxysilanc 3i Coupling Agent (psi) Jeffamine D400 173,700 Garnma-aminopropyltriethoxy silane 92,500 As can be seenfrom the foregoing Table, the use of 30 Gamma-glycidoxypropyltrimethoxysilane 104.400 amino acid coupling agents in accordance with theGanma'mercapmpmpylmmcthmy Gamma-methacryloxypropyltrimethoxy silane192.]00 practice of this invention provides glass fiber bundles whichhave markedly improved adhesion to rubber as compared to glass fiberbundles in which the glass The Jeffamine D 400 is an amine having theformula bers were sized with the conventional organo silicon couplingagents of the prior art.

EXAMPLE 2 H NCH-CH (O-CH,i )u-NH, Using the procedure described inExample 1, a size H3 Ha composition is prepared as follows: 40

Size Composition having an average molecular weight of 400.

As can be seen from the foregoing Table, the polyamine cou lin a ent ofthe resent invention rovided Polyethylene (Quaker Quasoft HS-60) l0.0%by wt. I fb E d l p d h d Glycine 12% by WL a g ass i er rein orce poyester ro aving improve Water 88-8 y tflex strength as compared to allof the organo silicon compounds used as coupling agents with theexception of the gamma-methacryloxypropyltrimethoxy silane. Thiscomposltloh was PP to glass fibers as they As will be appreciated bythose skilled in the art, the were formed; the resulting sized glassfibers were then size composition described in Example 1 can also bedried at an elevated temperature, formed into bundles employed in thetreatment f glass fib f use as and impregnated with an lmpl'eghatlhgCompost inforcement for resinous material in addition to glass tloh ofthe p described above formulated to cohtalh fibers for use asreinforcement for elastomeric materia dical'boxylated butadtehe'styl'ehep y als. Similarly, glass fibers treated in accordance with theprocedure of Example 3 can likewise be subjected ImpregnatingComposition to impregnation with an impregnating composition of the typedescribed above in the manufacture of bundles Pans By weigh! Solids ofglass fibers for use as reinforcement for elastomeric materials.Rcsorcinol-formaldchwlic 3" Additional size compositions of thisinvention are il- Butadiencstyrenc viny pyri inc lcrpolymcr 30 lustratedby the following examples.

Dicarhoxylatcd butadienc-styrcnc resin (Pliolitc 412]) Microcrystallincparaffin wax 7 After drying and curing of the resulting impregnated 6bundles, the bundles were combined with rubber to test the adhesion ofthe impregnated bundle to the rubber. Comparable results were obtained.

EXAMPLE 4 Size Composition 5 Saturated polyester resin 7.0% by wt. Fattyacid amine wetting agent (Nopcogcn 16L) 0.5% by wt. 4-Aniinopcntanoicacid 2.5% by wt. Water 90.0% by wt.

EXAMPLE Size Composition Polyvinyl alcohol 8.0% by wt.

The above size compositions can be used to treat glass fibers asdescribed in Examples 1 to 3 to promote a secure bonding relationshipbetween glass fibers and resinous or elastomeric materials.

In fabricating the combinations of glass fibers treated in accordancewith the practice of this invention, with elastomeric materials, theglass fibers or bundles of glass fibers are mixed with the elastomericmaterial or otherwise laid down in the desired arrangement forcombination with the elastomeric material, as in the manufacture ofglass fiber reinforced belts or in the manufacture of rubber tiresreinforced with cords of glass fibers. The combinations of glass fibersand elastomeric materials are then processed in a conventional manner bymolding and curing under heat and pressure or by vulcanizing foradvancement of the elastomeric materials to a cured or vulcanized statewhile in combination with the treated glass fibers whereby the bundlesof glass fibers become strongly integrated with the elastomeric materialin the glass fiberelastomeric product.

It will be understood that invention exists not only in the compositionsdescribed but also in the process in which the compositions are employedin the treatment of glass fibers as well as the treated or impregnatedglass fiber products formed thereof.

It will be understood that changes may be made in the details offormulation and methods of preparation without departing from the spiritof the invention, especially as defined in the following claims.

We claim:

1. Glass fibers having a thin coating thereon, said coating being formedfrom a film-forming binder selected from the group consisting ofpolyolefins; polymers of butadiene; copolymers of maleic anhydride andan unsaturated monomer selected from the group consisting of aconjugated diene, an alkyl acrylate, an alkyl methacrylate and a vinylaromatic monomer; polyvinyl alcohol; polyvinyl acetate; polyvinylchloride; polyepoxides and polyesters and an amino acid containing 2 to12 carbon atoms, with the coating containing 0.5 to 5 parts by weight ofthe amino acid for each 2 to 25 parts by weight of the binder.

2. Glass fibers as defined in claim 1 wherein the binder is apolyolefin.

3. Glass fibers as defined in claim 1 wherein the binder ispolyethylene.

4. Glass fibers as defined in claim 1 wherein the amino acid has theformula wherein x is an integer from 1 to 1 l.

5. A bundle of glass fibers for use as reinforcement for elastomericmaterials comprising a plurality of glass fibers, a thin film coating onthe surfaces of the individual glass fibers, said coating formed from afilmforming binder selected from the group consisting of polyolefins;polymers of butadiene; copolymers of maleic anhydride and an unsaturatedmonomer selected from the group consisting of a conjugated diene, analkyl acrylate, an alkyl methacrylate and a vinyl aromatic monomer;polyvinyl alcohol; polyvinyl acetate; polyvinyl chloride; polyepoxidesand polyesters and an amino acid containing 2 to 12 carbon atoms, withthe coating containing 0.5 to 5 parts by weight of the amino acid foreach 2 to 25 parts by weight of the binder, and an impregnant in thebundle, said impregnant comprising a blend of a resorcinolaldehyde resinand an elastomer.

6. A bundle of glass fibers as defined in claim 5 wherein the binder isa polyolefin.

7. A bundle of glass fibers as defined in claim 5 wherein the binder ispolyethylene.

8. A bundle of glass fibers as defined in claim 5 wherein the amino acidhas the formula wherein x is an integer from 1 to ll.

9. A bundle of glass fibers as defined in claim 5 wherein the blendcontains 2 to 10% by weight of the resorcinolaldehyde resin and 15 to60% by weight of an elastomer.

10. In a glass fiber reinforced elastomeric product in which anelastomeric material constitutes a continuous phase through which theglass fibers are dispersed, the improvement in the bonding relationshipbetween the glass fibers and the elastomeric material comprising acoating on the individual glass fibers, said coating being formed from afilm-forming binder selected from the group consisting of polyolefins;polymers of butadiene; copolymers of maleic anhydride and an unsaturatedmonomer selected from the group consisting of a conjugated diene, analkyl acrylate, an alkyl methacrylate and a vinyl aromatic monomer;polyvinyl alcohol; polyvinyl acetate; polyvinyl chloride; polyepoxidesand polyesters and an amino acid containing 2 to 12 carbon atoms, withthe coating containing 0.5 to 5 parts by weight of the amino acid foreach 2 to 25 parts by weight of the binder.

11. A product as defined in claim 10 wherein the glass fibers are in theform of a bundle and the bundle includes an impregnant therein, saidimpregnant comprising a blend of a resorcinol-aldehyde resin and anelastomer.

1. GLASS FIBER HAVING A THIN COATING THEREON, SAID COATING BEING FORMEDFROM A FILM-FORMING BINDER SELECTED FROM THE GROUP CONSISTING OFPOLYOLEFINS, POLYMERS OF BUTADIENE, COPOLYMERS OF MALEIC ANHYDREDE ANDAN UNSATUATED MONOMER SELECTED FROM THE GROUP CONSISTING OF A CONJUGATEDDIENE, AN ALKYL ACRYLATE, AN ALKYL METHACRYLATE AND A VINYL AROMATICMONOMER, POLYVINYL ALCOHOL, POLYVINYL ACETATE, POLYVNYL CHLORIDE,POLYEPOXIDES AND POLYESTERS AND AN AMINO ACID CONTAINING 2 TO 12 CARBONATOMS, WITH THE COATING CONTAINING 0.5 TO 5 PARTS BY WEIGHT OF THE AMINOACID FOR EACH 2 TO 25 PARTS BY WEIGHT OF THE BINDER.
 2. Glass fibers asdefined in claim 1 wherein the binder is a polyolefin.
 3. Glass fibersas defined in claim 1 wherein the binder is polyethylene.
 4. Glassfibers as defined in claim 1 wherein the amino acid has the formula
 5. Abundle of glass fibers for use as reinforcement for elastomericmaterials comprising a plurality of glass fibers, a thin film coating onthe surfaces of the individual glass fibers, said coating formed from afilm-forming binder selected from the group consisting of polyolefins;polymers of butadiene; copolymers of maleic anhydride and an unsaturatedmonomer selected from the group consisting of a conjugated diene, analkyl acrylate, an alkyl methacrylate and a vinyl aromatic monomer;polyvinyl alcohol; polyvinyl acetate; polyvinyl chloride; polyepoxidesand polyesters and an amino acid containing 2 to 12 carbon atoms, withthe coating containing 0.5 to 5 parts by weight of the amino acid foreach 2 to 25 parts by weight of the binder, and an impregnant in thebundle, said impregnant comprising a blend of a resorcinolaldehyde resinand an elastomer.
 6. A bundle of glass fibers as defined in claim 5wherein the binder is a polyolefin.
 7. A bundle of glass fibers asdefined in claim 5 wherein the binder is polyethylene.
 8. A bundle ofglass fibers as defined in claim 5 wherein the amino acid has theformula
 9. A bundle of glass fibers as defined in claim 5 wherein theblend contains 2 to 10% by weight of the resorcinolaldehyde resin and 15to 60% by weight of an elastomer.
 10. In a glass fiber reinforcedelastomeric product in which an elastomeric material constitutes acontinuous phase through which the glass fibers are dispersed, theimprovement in the bonding relationship between the glass fibers and theelastomeric material cOmprising a coating on the individual glassfibers, said coating being formed from a film-forming binder selectedfrom the group consisting of polyolefins; polymers of butadiene;copolymers of maleic anhydride and an unsaturated monomer selected fromthe group consisting of a conjugated diene, an alkyl acrylate, an alkylmethacrylate and a vinyl aromatic monomer; polyvinyl alcohol; polyvinylacetate; polyvinyl chloride; polyepoxides and polyesters and an aminoacid containing 2 to 12 carbon atoms, with the coating containing 0.5 to5 parts by weight of the amino acid for each 2 to 25 parts by weight ofthe binder.
 11. A product as defined in claim 10 wherein the glassfibers are in the form of a bundle and the bundle includes an impregnanttherein, said impregnant comprising a blend of a resorcinol-aldehyderesin and an elastomer.